Automatic-exchange circuit.



PATENTED DEC. 11', 1906.

A. M. BULLARD. AUTOMATIC EXCHANGE CIRCUIT.

APPLICATION FILED MAB- 10. 1906.

UNITED STATES PATENT OFFICE.

ALBERT M. BULLARI), OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECWtIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

Specification'of Letters Patent.

Patented Dec. 11-, 1906.

Application filed March 10, 1906. Serial No. 305.287.

To 11]] whom it may concern.- Be it known that I, ALBERT ill. BULLARD, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Automatic- Exchange Circuits, of which the following is a full, clear, concise, and exact description.

My invention relates toa telephoneexchange system wherein both manual and automatic exchanges are employed to unite a subscriber of the manual exchange with a subscriber of the automatic exchange' In .the operation of such a system-it often becomes necessary for the automatic-exchange subscribe-r, who has been called through the medium of a selector associated with a trunkline leading to a neighboring manual exchange, to signal the manual-exchange operator who supervises the connection in order to make a complaint or give an order to such operator and the object of my invention is to provide a system wherein an automatic subscriber who has been called by the manualexchange operator and whose lineisv connected with the operators cord-circuit may readily signal such operator over the trunkline connecting his line with the manual operators cord-circuit. In systems of this character heretofore in use it has been im possible for a called automatic subscriber to signal the manual operatorwith whose cordcircuit his line is connected, except where a number of trunk-lines lead from the automatic exchange to the manual exchange, in whichcase the called subscriber can select an idle trunk-line by operating his individual line-selector. trunk-line connecting the exchanges, a called automaticexchange' subscriber wishing to communicate with the manual-exchange operator could not signal her, for if he operates his line-selector tomake connection with the terminals of'the trunk-line thereon he will be locked 'out therefrom and receivev a busy.

signal, because the desired line that' is, the

trunk-linefhas effected a selective operation by means of its selector, and has therefore put the busy test on its multiple terminals, thus looking out all automatic subscribers, including the one connected with said selector so far as reverse signaling is concerned. With my plan the automatic called subscriber is provided with a key at his station,

If, however, there is but one which when depressed causes ringing current to be applied directly to the trunk-line to operate a signal at the manual exchange. To this end I connect a normally resting contact of the line-selector arm of each subscriber (which selector is of course idle when its lineis called) with one of its terminals upon the trunkselector, a condenser being iincluded between said connection and the called line. The ringing-key when operated causes pulsating ringing-current to be connected with the selector-arm of such called line, and this current passes over the'trunkto traverse any condensers at t e automatic exchange which would interfere with proper operation of the signal and without affecting, due to the condenser referred to, the bells of any other stations which might be connected withthe called subscribers line.

I will describe my invention by reference to the accompanying drawing, which is a diagram representing a telephone-exchange embodying my invention.

The manual exchange A is provided with a spring-jack a, forming the terminal of a trunk-hne extending in two limbs 1 2 to its multiple terminals 1 2 at the automatic exchange B, normally open branches 1"2 leading from conductors 1 2 to the selector- I arms 5 b of the trunk-selector b at the automatic exchange'B, said selector having terminals b b of all the lines in the automatic .exchange. As shown, a selector is provided for each limb of the trunk-line; but in practice a single selector would be employed, comprising a contact-arm carrying a pair of contacts adapted to trail over th'e line-contacts.

At the manual exchange theoperator is provided with a pair of link conductors 3 4, terminating in a plug a, which is adapted to be inserted within jack a to unite said link line and through the signal device at the. 1 manual exchange without bein called upon conductors with the trunk-line, link contromagnetic signal device F is provided in a bridge of the link conductors.

At the automatic exchange the trunk-line is provided with a bridge 5, including a grounded battery E, having its free pole con- Ioo the arms I) b".

thewatery and trunlaconductors 1 2, respectively, relay c controlling the operation of the stepping and retaining magnets d d of the selector b. A conductor 6 extends from the free pole of battery Ethrough armature c of relay c and its normally open front contact through normally closed contacts e of a test-relay e, through the retaining and stepping magnets d d in series, through the armature f .and its back contact 'of cut-off relay through the armature c and its back contact of relay 0, to the grounded ole of battery E. The cut-oil relay is inch-u ed in a branch conductor 7, connected with cond'uctor'i between the stepping-magnet and armature f, said conductor 7 being connected with the grounded pole of battery E. The step ing-rnagnet is provided with an armatureadapted when attracted to advance a ratchetwheel d the shaft whereof carries the contact-springs b b, and the are mature (2" oil? the retaining-magnet carries a detent ada ted when said armature is attracted to old the ratchet-wheel in its advanced position. v i The interrupter C-comprises a controllerarm- 9*, loosely mounted on a shaft and ada ted to be moved forward against the tension of a suitable spring and whenreleased' to rotate a ratchet-wheel g a distance corresponding to the forward movement of the arm. Said arm when away from normal position seyers the connection between link condnce tors 3 4 and connects conductor twi-th a'contact g; adaptedtobe alternately connected with a grounded contact 9 by the movement of said ratchet-wheel. When plug a is insorted into jack 0, a metallic circuit is coml eted', extending from the positive pole of ttcry E, over conductor 5, through relay 0, runleconductorl, to the manual exchan e, conductor 3', through the windings 0% a repeating --coil and impedance-coil to link conductor 4!, and back by way of conductors 2 5 tothe negative pole of the battery E, conductor 5 including relay 0. The operator at the manual exchange may now step the se- Pector-s rings 6 5 into engagement with the desired inc-terminals by operating her interrupter'C, which opens the circuit of trunk liInb I, rendering relay 0 inert, and applies a number ofgrou-nd connections by springs g g to trunk-conductor 2 corresponding to the number of the line wanted. Each time a ground is thus applied a circuit is completed from grounded contacts g over lin conductor 4, trunk conductor 2', conductor 5 including relay 0, to the free pole of grounded battery Each time the relay 6 is thus energized it completes acircuit 5 6 5 to operate the stopping and retaining magnets and advance Then the arm comes to rest upon the desired terminals; the interrupter in he y 'D,

l'ni

nected 'tt'ill mink-conductor A pair of returns to zero and restores the connection of 'rehwe 4: is included in said nige between conductors 3 4. The relay fis new energized in a circuit 5 6 7 5, said relay being short-circuited by the back contact" of armature C during selection. When said relay is energized, it completes at itsarmature f 'and front contact the continuity of conductor 2", which thereupon connects conductor 2 directly with its selector-arm 1;, while its armature f 3 extends conductor 8, which is connected with a source of ringing-current, through armature c of relay 0 to the'back contact of armature c of'relay'c, said arma- I ture 0 being included in conductor 1* and connected directly with one arm I) of selector b. The selector-arms while away from normal position disconnect the multi leterminals 1: 2 from the trunk-line an apply busy test to terminals 2 also continuing the connection of conductor 1 through a portion -of conductor 1 the front contact of armature c of relay 0.

In case the line wan-ted had been busy a test potential would have been found on the terminals of the line to which selector-arm of limb 2 is connected and a current would pass over conductor 2 to armature and back contact of cut-oil relay f, said back contact being connected with a conductor 9, lea through a quick-acting test-relay 6, through the armature c and front contact 0t relay 0 to earth. Said relay e would thereupon become energized before the sluggish relay f had time to respond and open at its contacts 6, the circuit of the stepping and retaining magnets, causing the selector-arms to return to zero, said relay e also applying at its contacts e a busy-test current to the trunk-line.

Let us assume that the trunk-selector has completed connection with line 60-, the terminals whereoi are connected by conductors 10' 11 with the station of such line. The operator at exchange A now operates herringwhich sevens connection of conductors 3 4 and g'roiinds conductor 4, thereby rendering relay cincrt andcansi-ng relay 0 to remain energized. The conductor 8, including the source of ringing-current, is now connected directly with the portion of conductor 1 connected with selector-arm'b', and ringing-current passes over conductors 8, 1 and 10, .through the called-subscribers bell, and back over limb 11, conductors 2 5 toground. i A

The telephone linefifl isproyided at the central oifice with a selector is and mechanism similar to that associated with the trunkline, relays h h and 'a-battery E being included in a bridge 5 of the conductors t0 1 1, a condenser i being inter osed conductor 11 between bridge 5 a the line-terminal, and a condenser t" being included in conductor 1*; so that the two lineshave independent talking-current supplies.

The selector-arm 1c of limb 10 of line 60 is connected with a conductor 8, which extends through armature k and its front contact of relay h, armature Z and its front contact of c'ut-ofl relay Z of the line, to a source of grounded pulsating ringing-current G,

while the firstcontact of the line-selector, which has heretofore been unused electric-- ally, being simply a dead terminal, is connected by a conductor 12 with conductor 11 between the terminal of the line on the trunkv selector and condenser 'i.

When the subscriber at station 60 in reopens conductor 10, causing relay h to retract its armature and connects limb 11 to ground, whereu on'a circuit from the .free

pole of grounde battery E is completed for relay h by way ofconductors 5 11 to earth.

Rela it being inert and relays k and Z energize conductor 8 is completed and ringingcurrent from the source Gfiows over the ,following path: Conductor 8", selector-ariii k, which is resting on its normal contact, conductor 12 limbdl of the line 60, contacts I) b of the selector, conductors 2 2 of the trunk-line, link conductor 4 through the operators signal F andback over link conduc-,

tor 3, trunk-conductor 1, bridge 5, to ground. Thus no condensers are interposed in, the ringing circuit in series with the condenser in serieswith the oper'ators signal, while the condenser t, necessarily in the line-circuit, is

interposed in series with the bells of other stations of line 60, resulting in the operation of the said signal and the non-operation of the said bells.

The limb 10' is normally disconnected from its selector-armJc at contacts m m, which are connected when the selector-arm is away from normal position. This prevents a lowresistance shunt upon the line by way of arm 7c, its normal contact and conductor 12, when the relay h is energized.

I claim v 1. 'The combination with a manual telephone-exchange, of an automatic exchange, a number of telephonedines extending from substations to said automatic exchange, a trunkdine extending between said exchanges, a signal device adapted to be connected with said trunk-line'at the manual exchange, a selector for the trunk-line at the automatic ex? Change, means controlled from the manual exchange for operating said selectortoconnfect said trunk-line with any one of said telephone-lines, a ringing-key at the substation of said called line and means controlled by said key for applying current to said trunk line, tooperate said signal device.

2. The combination with a manual telephone-exchange, of an automatic telephoneexchange, a number of telephone-lines ex tending from substations to said automatic telephone-exchange, a selector for each line at the automatic exchange for connecting said line with another line in said exchange, a trunk-line extending from the manual exchange to the automatic exchange, an electromagnetic signal adapted to be connected with the trunk-line at the manual exchange, a selector connected with the trunk-line at the automatic exchange adapted to connect said trunk-line with anyone ofsaid tele phone-lines, a source of ringing-current, a ringing-key at the called station, and means controlled by said key and the called-sub 'scribers selector for applyin ringing-current from said source to the tru -line to operate said signal device.

3. The combination with a manual telephone-exchange, of an automatic exchange, a number of telephone-lines extending from substations'to said automatic exchange, a se-' lector for each line at the automatic exchange, said selector comprising a contactarm controlled from the station of said line, and adapted to sweep over the terminals of the other lines to connect saidiline with a de sired line, a trunk-line:extending from the manual exchange to the automatic exchange, an electromagnetic signal device at the manual exchange adapted to be connected with said trunk-line, a selector connected with said trunk-line in the automatic exchange adapted to connect said line with the terminal of any line in the exchange, a conductor extending from the normal resting contact of each line-selector to the terminal of such line upon the trunk-selector, a source of ringing-current, and means controlled from the station of a line with which such trunk-line is connected for connecting said source of ringing-current with the individual selector-arm of such line'to operate said electromagnetic signal device at the manual exchange.

4. The combination with a manual telephone-exchange, of an automatic exchange, a number of metallic circuit telephone-lines extending from substations to said automatic exchange, a selector for each line at the automatic exchange comprising an arm carrying contacts of said line and adapted to sweep over the terminals of the other lines to connect said line therewith, a metallic circuit trunk-line extending from the manual exchange to the automatic exchange, an electromagnetic signal device adapted to belconnected with the trunk-line at the manual exchange, a selector at the manual exchange havin contacts on its movable arm connecte with said trunk-line, terminals on said selector connected with said telephone-lines,

' lector-arm of a called line with one 'of its terminals upon the trunk-selector, a source of grounded ringing-current, and electromagnetic mechanism controlled from the called station for connecting said source of ringing- I current with said selector-arm contact to-op"- erate the signal device at the manual exchange.

5 The combination with a manual telephone-exchange, of an automatic exchange, 'a number of metallic circuit telephone-lines extending from-substations to said automatic exchange, a selector for each line at the automatic exchange comprisin an arm carrying a pair of contacts and a apted to sweep over t e terminals of the other line to connect its line therewith, a metallic circuit trunkline extending from said: manual exchange to the automatic exchange, an electromagnetic.

signal device adapted to be connected in a bridge of the trunk-line at the manual exchange, a selector atthe automatic exchange having contacts on its -movable arm connected'with said trunk-line, terminals upon said selector connected with the said telephone-lines, a relay with a source of ground ed current in a bri'dgeof the trunk line at the automatic-exchange adapted to operate said trunk-selector under the control of the mani ual operator to connect the trunk-line with rent in a bridge of the called line said bridge, connected circuits between a conductor extending from the normal resting terminal of one contact of the selectora relay 1n one limb of such line upon the trunk-selector, the condenser in such line being located between the connection of suc grounded ringing-current, and 'a key .atva called station for operating the relay in its bridge at the exchan e, to apply current from said source to sai selector-arm contact of such line to operate the signal device at the manual-exchange. x

6. The combination with a manual telephone-exchange, of an automatic telephoneexchange, a number of telephone-lines extending from substations to said automatic exchange, a selector for each tomatic exchan e, a trunk-line extending between said exc anges, a slgnal associated to connect said trunk-line with any one of said telephone-lines, and means controlled from a substation of the line with which said trunk-selector makes connection, and by the individual selector of said called line, for opcrating said signal. In witness whereof I hereunto subscribe I my name this 5th day of March A. D. 1906.

ALBERT M. BULLARD.

I Witnesses:

JENNIE C. LAMB,

GEORGE A. HAMILTON.

the terminals of a called line, a source of curs.

condensers in the limbs of said" the said bridges,

conductor, therewith and the called line, a source of line at the auwith the trunk-line at; the manual exchange I a selector at the automatic exchange adapted arm of each subscribers line to a t'ermmal of I 

